The ability to build extremely small devices via recently discovered micro- and nano-fabrication processes has opened the door to the possibility of electromechanical machines and sensors of a size existing only in the realm of science fiction in previous generations. For instance, many methods now exist to build working microelectromechanical systems (MEMS) as well as even smaller nanoelectromechanical systems (NEMS). While the technology to build these devices is continuing to expand and grow, practical applications for such devices remain elusive. Problems currently faced by researchers in taking this final step often center around the challenges to be overcome in regard to communicating to the macroscopic world the mechanical motion and/or the electronic signals generated on the micro- or nano-sized scale. For instance, as the devices are so small, the capacitance of a signal junction can approach the unavoidable parasitic capacitance due to the existence of junctions between components of the device, as well as the resting capacitance of the device itself. As such, the devices can describe an extremely low signal to noise ratio, making the detection of an electrical signal very difficult, if not impossible.
Some of the primary mechanical elements being utilized in the development of MEMS and NEMS technology include micro- and nano-sized cantilevers, clamped beams, and the like. Such devices are often used in sensing or actuating technologies and are generally based upon the changes in a property of the cantilever or beam due to absorption or adsorption of a species at the surface or due to changes in the physical characteristics of a sample including, for instance, pressure/acceleration changes, magnetic force changes, temperature changes, and/or extremely small changes in mass. Detection of change in resonant frequency of a device is one particular mechanical property that has been used in many such regimes. Changes in the oscillating or resonant frequency of a micro- or nano-sized beam have generally been limited to determination through optical detection, e.g., analysis of the deflection properties of a laser directed at a reflecting surface of the cantilever, analysis and detection of changes in the resistivity of a piezoresistor integrated into the cantilever, or analysis of magnetically induced signals.
Difficulties exist with these detection methods, however. For instance, optical detection techniques require optical access to the cantilever as well as the utilization of relatively expensive laser technologies. Integration of a piezoresistor to a cantilever so as to detect changes in resistivity on the material can necessitate increase in size as well as cost of the apparatus. Also, the large magnetic fields required in magnetic systems can be difficult and expensive to establish. Accordingly, there remains room for variation and improvement within the art.